29topic_9b_f07

29topic_9b_f07 - Simple Primary Tissues Parenchyma This is the filler tissue of the plant Simple Primary Tissues Parenchyma The regions of the

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Unformatted text preview: Simple Primary Tissues: Parenchyma This is the filler tissue of the plant. Simple Primary Tissues: Parenchyma The regions of the shoot and root that are primarily composed of parenchyma are the pith and cortex. Simple Primary Tissues: Parenchyma Parenchyma is also found in regions around the vascular bundles and is known as interfascicular parenchyma. Simple Primary Tissues: Collenchyma Collenchyma tissue is a protective tissue found as strands or continuous cylinders beneath the epidermis in stems and petioles. Simple Primary Tissues: Collenchyma In dicot leaves it is a protective layer around the vascular bundles (veins). Simple Primary Tissues: Collenchyma When you bite into celery the crunch is due to collenchyma strands. Simple Primary Tissues: Sclerenchyma Sclerenchyma is also a protective tissue either composed of sclerids or more commonly fibers. Sclerids are found in leaves and fruits and as a wound tissue Fiber sclerenchyma is found as layers underneath the epidermis and/or associated with the phloem of the vascular system. Fibers are a significant part of wood. Simple Primary Tissues: Sclerenchyma Sclerenchyma is also a protective tissue either composed of sclerids or more commonly fibers. Simple Primary Tissues: Sclerenchyma Sclerids are found in leaves and fruits and as a wound tissue Simple Primary Tissues: Sclerenchyma Fiber sclerenchyma is found as layers underneath the epidermis and/or associated with the phloem of the vascular system. Simple Primary Tissues: Sclerenchyma Fibers are a significant part of wood. Fibers in Wood Complex Primary Tissues: Leaf Mesophyll The mesophyll of leaves has two primary regions the palisade mesophyll and the spongy mesophyll. Complex Primary Tissues: Leaf Mesophyll Within the leaf is the vascular system which is composed of veins. Complex Primary Tissues: Leaf Mesophyll Around the veins is a layer of parenchyma cells called the bundle sheath and some of these cells, the so called "transfer cells" are specialized for loading sugar into the phloem. Complex Primary Tissues: Leaf Mesophyll At the tips of some leaves water droplets are extruded from the vascular system. This process known as guttation occurs where a vein ends with a special structure the hydathode. Complex Primary Tissues: Guttation Complex Primary Tissues: Hydathode cuticle sheath epithem water cavity sheath tracheids stoma Complex Primary Tissues: Leaf Epidermis The epidermal cells secrete various materials including a waxy material called cutin that coats the surface of the leaf and is called a cuticle. Complex Primary Tissues: Leaf Epidermis In addition there are specialized cells called guard cells that comprise the stomata and which are associated with helper cells called subsidiary cells. Complex Primary Tissues: Leaf Epidermis The epidermis of many plants have hairs called trichomes which are multicellular outgrowths of the epidermis. Complex Primary Tissues: Xylem The xylem is the tissue responsible for the upward transport of water and minerals. water moves to the xylem and up the plant apoplastic flow symplastic flow endodermis pericycle xylem Complex Primary Tissues: Xylem The cells of the xylem develop secondary cell walls. Complex Primary Tissues: Xylem The conducting cells of the xylem are vessel elements and/or trachieds. Complex Primary Tissues: Xylem The xylem also contains parenchyma and fibers. Fibers in Wood Complex Primary Tissues: Xylem The first formed vessel elements are called protoxylem and the latter formed elements are called metaxylem. dicot root cross section Dicot Root Vascular Cylinder developing dicot root protostele immature metaxylem phloem pericycle mature protoxylem endodermis dicot root mature protostele endodermis pericycle primary phloem primary xylem primary phloem dicot stem cross section protoxylem pericycle mature phloem metaxylem endodermis monocot root immature vascular cylinder monocot root mature vascular cylinder protoxylem endodermis phloem pericycle 1. apical meristem Dicot Stem Vascular Transition 2. procambium 3. protoderm 4. ground meristem 5. primary phloem 6. primary xylem 7. leaf trace 8. pith ray 9. pith 10. epidermis Complex Primary Tissues: Phloem The phloem is the tissue responsible for the bi-directional movement of sugar throughout the plant. Complex Primary Tissues: Phloem Except for fibers, the cells of the phloem are all living and only have primary walls. Complex Primary Tissues: Phloem The conducting cells of the phloem are the sieve tube members which are aided by the companions cells. Complex Primary Tissues: Phloem Parenchyma cells are present as a filler tissue. ...
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This note was uploaded on 04/08/2008 for the course BIO 29 taught by Professor Mcgowan during the Spring '08 term at CUNY Brooklyn.

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